You probably remember the first time you heard it. That bouncy, almost saccharine electric piano melody that kicks in when Noelle Holiday—the literal girl next door—shuffles up to Kris and Susie in the hallway. It’s track 49 on the Deltarune Chapter 2 OST. It feels safe. It feels like 2000s sitcom music.
But if you’ve spent any time in the Deltarune community, you know Toby Fox doesn’t do "just cute."
Girl Next Door Deltarune is a masterclass in musical gaslighting. While the song presents itself as a bubbly theme for a shy classmate, it’s actually the foundation for some of the darkest lore in the game. Honestly, once you hear the connections to Gaster and the tragedy of the Holiday family, the "feel-good" vibes of this track start to feel a lot more like a mask.
The Melody That Isn't Just Noelle's Theme
Most players assume this is just "Noelle’s Theme." That makes sense, right? It plays when she’s onscreen. It sounds like her personality: polite, nervous, and a little bit "Christmas-coded." But Toby Fox dropped a bombshell in a 2019 Twitter post (and later in the 6th Anniversary stream) where he basically said that while people call it Noelle’s theme, it’s actually a song that gets used repeatedly throughout the game, even when she isn't around.
That’s weird.
If it’s not strictly her theme, what is it? Some fans argue it's actually the theme of the Holiday family as a whole, or perhaps a leitmotif for "the girl who is gone."
The Lost Girl Connection
You can't talk about Girl Next Door Deltarune without talking about its sister track, "Lost Girl." They share the same primary melody, but the vibe is night and day.
- Girl Next Door: 118 BPM, upbeat, major key energy, bright synth.
- Lost Girl: Slower, melancholy, heavy on the piano, dripping with longing.
Basically, "Girl Next Door" is the version of Noelle the world sees. The high-achieving student, the daughter of the Mayor, the girl who likes Susie from a distance. "Lost Girl" is the version of Noelle (or her missing sister, Dess) that exists when the lights go out. It’s the sound of grief.
Wait, Is Gaster in the Piano?
Okay, let's get into the tinfoil hat stuff that might actually be true. If you slow down Girl Next Door Deltarune or look at the MIDI data, there are these specific four-note sequences that mirror the "Gaster's Theme" leitmotif from Undertale. Specifically, the background notes during the B-section of the track.
Is Noelle connected to the man who speaks in hands?
Maybe. She’s one of the few characters Gaster (or the "Goner Maker" narrator) reacts to. If you name your creator "Noelle" in Chapter 1, the game tells you that you are about to meet someone "very, very wonderful." The only other characters that trigger this are Kris and Susie.
This isn't just a catchy tune. It's a breadcrumb.
The Dark Side of the "Girl Next Door"
There’s a reason this track feels so different after you’ve played the Snowgrave (Weird) Route. In that version of the game, Noelle is manipulated into committing horrific acts of violence. The "innocent" girl next door archetype is shattered.
When you look back at the song "Girl Next Door," the cheerfulness starts to feel forced. It’s like a facade of normalcy covering up a family that has lost a daughter (Dess), a father who is dying in a hospital bed (Rudy), and a mother who is so cold she’s literally the Mayor of a town that feels like it's holding its breath.
Why the Song Plays During the "Moss" Scene
This is a detail that bothers a lot of people. In the Dark World, there’s a recurring joke where Kris and Susie eat moss. In Chapter 2, when they do this, Girl Next Door Deltarune (or a variation of it) plays.
Why?
Some theorists, like those on the r/krusie_gang subreddit, think it implies Susie is actually the "girl next door" to Kris. Others think it’s just Toby Fox messing with us. But the most likely answer is that the song represents a specific type of childhood nostalgia—the kind Kris, Susie, and Noelle all shared before everything went wrong. It's the sound of being a kid in Hometown.
Key Facts About the Track
If you're a music nerd, here's the breakdown of what's actually happening in the file:
- Leitmotif Usage: It shares a melody with "Ferris Wheel," "Lost Girl," and "findher.ogg."
- The "Slide": There is a prominent pitch-slide in the lead synth that gives it that slightly "wobbly" or "unsure" feeling.
- The Basement: Some people swear they hear the "Smile" sound effect (associated with Gaster) buried in the reverb of Noelle-related tracks.
What This Means for Future Chapters
We’re only two chapters into a seven-chapter game. If Girl Next Door Deltarune is already this layered, Chapter 3 and beyond are going to be wild. Noelle’s importance to the story—and specifically her role as "The Angel"—is tied directly to this music.
Spamton calls her "Angel," and the "Lost Girl" motif appears in the "Freedom" motif (which is tied to the Secret Bosses). Basically, this simple little song is the musical anchor for the entire "Heaven" and "Angel" plotline.
How to Use This Information
If you're trying to figure out where the story is going, stop looking at the dialogue and start listening to the background.
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- Watch for "Lost Girl" variations: When this melody appears in the Dark World, it usually means Noelle is having a moment of self-realization or extreme stress.
- Check the BPM: Changes in the speed of the Girl Next Door melody often signal how "in control" Noelle is.
- Listen for the background bells: The Holiday family is associated with Christmas sounds. If the bells stop, something is very wrong.
Honestly, the "Girl Next Door" isn't just a trope. In Deltarune, she might be the most dangerous person in the room. And her theme song is the first warning we ever got.
Next time you're walking through the school hallways in-game, listen to those first few notes. It's not just a bop. It's a eulogy for a version of Noelle that might not exist for much longer.
Actionable Insight: To see the "Gaster" connections yourself, use a program like Audacity to slow the track down by 50% and listen specifically to the secondary synth line during the 0:37 mark. You’ll hear a familiar four-note pattern that hasn't changed since 2015.